Synchronized etalon filters for standardizing WDM transmitter laserwavelengths

The authors report a simple technique to synchronize solid etalons which provides identical sets of equally spaced absolute reference frequencies. To demonstrate the principle, 1-mm-thick fused silica etalons were synchronized to have identical sets of resonant frequencies at 195.579±n×0.1034 THz, where n is any integer. These references were temperature-insensitive with the aid of a temperature control loop. These synchronized etalons could be used for standardizing the wavelengths of transmitter lasers in large-scale WDM wavelength division multiplexed networks